Protective effects of a novel drug RC28-E blocking both VEGF and FGF2 on early diabetic rat retina

AIM： To investigate protective effects of a novel recombinant decoy receptor drug RC28-E on retinal damage in early diabetic rats. METHODS： The streptozotocin （STZ）-induced diabetic rats were randomly divided into 6 groups： diabetes mellitus （DM） group （saline, 3 μL/eye）; RC28-E at low （0.33 μg/μL, 3 μL）, medium （1 μg/μL, 3 μL）, and high （3 μg/μL, 3 μL） dose groups; vascular endothelial growth factor （VEGF） Trap group （1 μg/μL, 3 μL）; fibroblast growth factor （FGF） Trap group （1 μg/μL, 3 μL）. Normal control group was included. At week 1 and 4 following diabetic induction, the rats were intravitreally injected with the corresponding solutions. At week 6 following the induction, apoptosis in retinal vessels was detected by TUNEL staining. Glial fibrillary acidic protein （GFAP） expression was examined by immunofluorescence. Blood-retinal barrier （BRB） breakdown was assessed by Evans blue assay. Ultrastructural changes in choroidal and retinal vessels were analyzed by transmission electron microscopy （TEM）. Content of VEGF and FGF proteins in retina was measured by enzyme linked immunosorbent assay （ELISA）. The retinal expression of intercellular cell adhesion molecule-1 （ICAM-1）, tumor necrosis factor-α （TNF-α）, VEGF and FGF genes was examined by quantitative polymerase chain reaction （qPCR）. RESULTS： TUNEL staining showed that the aberrantly increased apoptotic cells death in diabetic retinal vascular network was significantly reduced by treatments of medium and high dose RC28-E, VEGF Trap, and FGF Trap （all P〈0.05）, the effects of medium and high dose RC28-E or FGF Trap were greater than VEGF Trap （P〈0.01）. GFAP staining suggested that reactive gliosis was substantially inhibited in all RC28-E and VEGF Trap groups, but the inhibition in FGF Trap group was not as prominent. Evans blue assay demonstrated that only high dose RC28-E could significantly reduce vascular leakage in early diabetic retina （P〈0.01）. TEM revealed that the ultrastructures in choroidal and retinal vessels were damaged in early diabetic retina, which was ameliorated to differential extents by each drug. The expression of VEGF and FGF2 proteins was significantly upregulated in early diabetic retina, and normalized by RC28-E at all dosages and by the corresponding Traps. The upregulation of ICAM-1 and TNF-α in diabetic retina was substantially suppressed by RC28-E and positive control drugs. CONCLUSION： Dual blockade of VEGF and FGF2 by RC28-E generates remarkable protective effects, including anti-apoptosis, anti-gliosis, anti-leakage, and improving ultrastructures and proinflammatory microenvironment, in early diabetic retina, thereby supporting further development of RC28-E into a novel and effective drug to diabetic retinopathy （DR）.

Identification of integrin β6 gene promoter and analysis of its transcription regulation in colon cancer cells

BACKGROUND The integrinβ6 gene,which is expressed in epithelial cancer,plays a pivotal role in various aspects of cancer progression.The present research for integrinβ6 regulation mainly focuses on the post-transcription and translation related regulation mechanism and its role in tumorigenesis.The mechanisms of how the integrinβ6 gene is regulated transcriptionally,and the promoter and transcription factors responsible for basic transcription of integrinβ6 gene remain unknown.AIM To clone and characterize the integrinβ6 promoter.METHODS Software analysis was used to predict the region of integrinβ6 promoter.Luciferase reporter plasmids,which contained the integrinβ6 promoter,were constructed.Element deletion analysis was performed to identify the location of core promoter and binding sites for transcription factors.RESULTS The regulatory elements for the transcription of the integrinβ6 gene were located between-286 and-85 and contained binding sites for transcription factors such as STAT3 and Ets-1.CONCLUSION For the first time,we found the region ofβ6 core promoter and demonstrated the binding sites for transcription factors such as Ets-1 and STAT3,which are important for integrinβ6 promoter transcription activity.These findings are important for investigating the mechanism of integrinβ6 activation in cancer progression.